1. Field of the Invention
This invention relates to methods and apparatus for identifying human beings, specifically to an improved method for reading and analyzing fingerprints. This invention is also useful for acquiring better quality fingerprints without the need of ink or lubricating gel for law enforcement applications.
2. Description of Prior Art
Fingerprints have been a safe means for uniquely identifying human beings for over one hundred years. So far there has not been a single instance of two human beings having the same fingerprints. Fingerprints have been used for human identification by law enforcement for a long time. Recently, as technology has become available, fingerprints have been used for real-time human being identification in access control applications, personal identification (ID), ID verification, in documenting the time of attendance, identification of intruders, and similar applications.
Despite the long history of fingerprints and the reliable identification that they offer, it has been very hard to achieve the same level of identification accuracy with an electronic fingerprint recognition system as is possible by an experienced fingerprint forensic analyst. The discrepancy in the level of identification accuracy with the existing electronic systems is attributed to various reasons. The main reasons primarily relate to:
(a) the weakness of existing electronic systems to extract the characteristic points (Minutiae) from a fingerprint reliably and consistently; PA0 (b) the weakness of the existing electronic scanners to compensate for natural variations and wear of the fingerprint due to dryness from dry and cold weather, the cracking due to hard water, soap, detergent, and contact with abrasive surfaces; PA0 (c) the weakness of existing software to compensate for the variations caused by the conditions enumerated in (b) above. PA0 (a) to provide a non-intrusive, non-objectionable means for fingerprint conditioning, whereas the prior art in this area provides non-friendly, intrusive, and messy substances for finger conditioning; PA0 (b) to provide a fingerprint processing and matching method that, in conjunction with object (a), guarantees negligible false acceptance probability at very low false rejection rate, whereas the prior art in this area has failed to deliver systems that reliably guarantee low false acceptance and low false rejection rates; PA0 (c) to provide an apparatus that incorporates both objects (a) and (b) to realize a high integrity, high reliability real-time fingerprint recognition system, whereas the prior art in this area does not have a system that provides acceptable means for conditioning fingerprints and matching techniques to guarantee the low false acceptance and false rejection rates acceptable in real-time fingerprint recognition systems; and PA0 (d) to provide an apparatus that can integrate fingerprint scanning capabilities with keypad technology and card reader technology and the software to go along with it, so as a security network can easily be built by daisy-chaining those apparatuses to allow for cost-effective security solution to realize an onion-like security concept, whereby the outermost vulnerable perimeter layer is protected by the use of fingerprint verifiable Personal Identification Numbers (PINs) or card passwords, and the less vulnerable interior layers may be protected by conventional keypad or card reader security devices that do not require user ID verification. The prior art in this area does not offer systems that are configurable for multiple ID elements, such as PIN, password, and fingerprints in any desirable combination all operating off the same database and capable of being connected on the same network. PA0 1. A method for accurately determining identity of a human being comprising the steps of: PA0 2. A method for achieving superior identification of a human being comprising the steps of: PA0 3. A method for improving the quality of a fingerprint image (126) from a dry, chapped, or dirty finger (123) of a human being, comprising: PA0 4. An apparatus for improving quality of a fingerprint image (126) of a human being comprising: PA0 5. An apparatus (128) for identification of a human being from fingerprints comprising: PA0 6. A method for the identification of a human being comprising: PA0 7. An apparatus for transmitting data on a serial RS232 port of a computer (106) over longer distance, comprising:
Substances that have been used traditionally by law enforcement to compensate for the tear and wear of the fingerprint of a human being include ink and clear gel. Both means of compensation are messy, leave residues on the finger, and thus completely inadequate for real-time fingerprint capturing for repetitive use of the fingerprint as required in access control applications, personal ID verification, time of attendance determination, and for intrusion control, etc.
Traditionally fingerprint identification systems rely on Minutiae to identify the person to whom the fingerprint belongs to. Minutiae are the points of termination of a ridge, or the points of bifurcation of a ridge in a fingerprint. Practically all methods of fingerprint matching from the Prior Art are based on Minutiae matching. Although Minutiae constitute an irrefutable means of fingerprint matching, the accuracy of Minutiae matching is questionable under a wide variety of finger conditions. For example Minutiae become very unreliable as a means of matching, when a fingerprint is chapped, dry and, in general, worn out from natural wear. Chapped, dry, or worn out fingerprints produce random sets of Minutiae either because ridges become fragmented or because they become very faint to detect. In either case, Minutiae become an unreliable means of accurately identifying fingerprints, and thus the identity of a human being from them.
In our invention, as it will become clear in the next section, the matching method that we use relies on fusing the information contained in the Minutiae with information extracted from another orthogonal set of features that relates to the ridge frequency. By ridge frequency, we imply the rate of succession between ridges and valleys in the fingerprint image at any given direction on the image plane. The ridge frequency information provides information that can be used to discriminate one fingerprint from another. This information is referred to as Meniscus or Global in the invention.
By fusion we mean the process of integrating two different sets of data in a meaningful way. In order to maximize the beneficial results from fusion, the data sets must be orthogonal in the sense that the information in one data set compliments the information from the other. This complimentarity of information is crucial in achieving enhanced performance after fusion of different data sets.
One important attribute of the Meniscus or Global feature set is that it is orthogonal to the Minutiae features in the sense that the microscopic Minutiae structures are not affected by the macroscopic Meniscus/Global ridge structures. This orthogonality is important in our invention, because it allows to fuse the information from the two feature sets in a complimentary fashion, thus enhancing the fingerprint matching accuracy beyond what is feasible by each method individually. Moreover, the two feature sets are structurally complimentary, so when one set becomes unreliable due to finger degradation, the other still maintains a level of quality that allows to do accurate identification. So, the orthogonality allows to use both sets synergistically by fusing them, and enhance the identification accuracy after fusion.
Fusion has been used in other fields and the inventors have many contributions in the field of fusion. However, fusion has never been applied before for human being identification by combining information contained in different orthogonal feature sets from the same fingerprint with the purpose to reduce or, even eliminate all together, the false rejection and false acceptance rates when matching one fingerprint against another. False rejection rate is defined as the rate of failure of a properly authorized human being. False acceptance rate is defined as the rate of acceptance of an unauthorized human being. Although fusion of Minutiae with Meniscus or Global features provides an identification method far superior in terms of accuracy than any method in the Prior Art, there are circumstances that a finger may be either extremely chapped, dry, or worn out from weather, temperature, manual labor, or dirt, that does not leave a trace (fingerprint) on the scanner to capture. Under these conditions, no identification method, no matter how sophisticated can be used for identification: the fingerprint it's not there. It is precisely this situation that our invention provides the only possible remedy for: a conditioning apparatus that when in contact with the finger releases a controlled amount of lubricant, or lubricant mixture, that rebuilds the fingerprint structure so that it becomes visible to the scanner. Furthermore, the same conditioning apparatus can be used to enhance the fingerprint quality so that tighter security levels can be used in a system that identifies human beings from fingerprints.